Investigation of the bipolar effect in the thermoelectric material CaMg<sub>2</sub>Bi<sub>2</sub> using a first-principles study

Gong, Ji‐Jun; Hong, Aijun; Shuai, Jing; Li, L.; Yan, Z. B.; Ren, Zhifeng; Liu, J.-M.

doi:10.1039/c6cp02057g

Cited by 104 publications

(60 citation statements)

References 47 publications

(87 reference statements)

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“…While the calculation of this effect is beyond the present work, we qualitatively analyzed the bipolar impact to S by calculating the contribution of thermally generated charge carriers ( Figures S23 and S24). 64 Results obtained clearly showed that in spite of the lower bandgap of Bi-CASe, and thus the higher charge carrier concentrations associated to thermal generation, the reduced effective mass for electrons in this compound should translate in a lower contribution of the minority carriers to S and thus to an overall higher Seebeck coefficient. A bipolar contribution could also explain the differences in the temperature dependence of κ L between Bi-CASe and pure CASe, but this point is to be confirmed.…”

Section: Resultsmentioning

confidence: 92%

Solution-based synthesis and processing of Sn- and Bi-doped Cu₃SbSe₄nanocrystals, nanomaterials and ring-shaped thermoelectric generators

et al. 2017

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Copper-based chalcogenides that comprise abundant, low-cost, and environmental friendly elements are excellent materials for a number of energy conversion applications, including photovoltaics, photocatalysis, and thermoelectrics (TE). In such applications, the use of solution-processed nanocrystal (NC) to produce thin films or bulk nanomaterials has associated several potential advantages, such as high material yield and throughput, and composition control with unmatched spatial resolution and cost. Here we report on the production of Cu3SbSe4 (CASe) NCs with tuned amounts of Sn and Bi dopants. After proper ligand removal, as monitored by nuclear magnetic resonance and infrared spectroscopies, these NCs were used to produce dense CASe bulk nanomaterials for solid state TE energy conversion. By adjusting the amount of extrinsic dopants, dimensionless TE figures of merit (ZT) up to 1.26 at 673 K were reached. Such high ZT values are related to an optimized carrier concentration by Sn doping, a minimized lattice thermal conductivity due to efficient phonon scattering at point defects and grain boundaries, and to an increase of the Seebeck coefficient obtained by a modification of the electronic band structure with the Bi doping. Nanomaterials were further employed to fabricate ring-shaped TE generators to be coupled to hot pipes and which provided 20 mV and 1 mW per TE element when exposed to a 160 °C temperature gradient. The simple design and good thermal contact associated with the ring geometry and the potential low cost of the material solution processing may allow the fabrication of TE generators with short payback times.Peer ReviewedPostprint (author's final draft

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Section: Resultsmentioning

confidence: 92%

Solution-based synthesis and processing of Sn- and Bi-doped Cu₃SbSe₄nanocrystals, nanomaterials and ring-shaped thermoelectric generators

et al. 2017

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“…Figure a is a schematic illustration of the bipolar effect in the thermoelectric materials, in which if a temperature gradient is imposed on a thermoelectric material with the hot‐end and cold‐end, more excitation of electrons/holes near the hot‐end than the cold‐end and more annihilation of electrons/holes near the cold‐end than the hot‐end will take place . This implies that more heat will be absorbed near the hot‐end due to the electron/hole excitation and more heat will be released near the cold‐end due to the electron/hole recombination, which enlarges κ . Also, the bipolar effects degrade S , because the thermally excited minority carriers have opposite S and offset those of majority ones …”

Section: Band Gap Enlargementmentioning

confidence: 99%

“…This implies that more heat will be absorbed near the hot‐end due to the electron/hole excitation and more heat will be released near the cold‐end due to the electron/hole recombination, which enlarges κ . Also, the bipolar effects degrade S , because the thermally excited minority carriers have opposite S and offset those of majority ones …”

Section: Band Gap Enlargementmentioning

confidence: 99%

Eco‐Friendly SnTe Thermoelectric Materials: Progress and Future Challenges

Moshwan

Yang

Zou

et al. 2017

Adv Funct Materials

338

260

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As a key type of emerging thermoelectric material, tin telluride (SnTe) has received extensive attention because of its low toxicity and eco-friendly nature. The recent trend shows that band engineering and nanostructuring can enhance thermoelectric performance of SnTe as intermediate temperature (400-800 K) thermoelectrics, which provides an alternative for toxic PbTe with the same operational temperature. This review highlights the key strategies to enhance the thermoelectric performance of SnTe materials through band engineering, carrier concentration optimization, synergistic engineering, and structure design. A fundamental analysis elucidates the underpinnings for the property improvement. This comprehensive review will boost the relevant research with a view to work on further performance enhancement of SnTe materials.where k B , e, h, m*, µ, and L are the Boltzmann constant, the carrier charge, the Planck's constant, the effective mass of the charge carrier, the carrier mobility, and the Lorenz number, respectively. As can be seen, S, σ, and κ e are interacted and conflict, which raises the difficulty to obtain high ZT. To solve these conflicts, extensive research has been carried out through band engineering to optimize S and σ, [5][6][7] and structuring to reduce the κ l . [8][9][10][11][12] Figure 1a summarizes recent significant achievements in different thermoelectric materials including SnSe, [25] 3%Na-(PbTe) 0.8 (PbS) 0.2 , [70] Cu 2 S 0.5 Te 0.5 , [71] and GeSbTe. [72] As can be seen, the current ZT values of the thermoelectric materials lie between 1 and 2, [7,[13][14][15][16][17][18][19][20][21][22][23] resulting in the fact that the current thermoelectric energy conversion efficiency is comparable to the other energy conversion technologies, such as photovoltaic cells, [22] and solar thermal plants. [22] Considerable research has been continuing to further drive ZT higher than 2 with the predicted efficiency over 20%, [24,25] which can attract highly exciting prospect in the energy generation and conservation fields.In terms of the industrial and automotive applications, waste heats are generally produced in the temperature range of 500-900 K. [26][27][28] To recover such waste heats, developing high-performance mid-temperature (400-900 K) thermoelectric materials is highly desired. For this purpose, lead telluride (PbTe) and its alloys have been considered as a primary material system. [7,10,14,17,29] However, the toxicity associated with Pb causes severe threat to the environment and needs to be alternated for domestic usage. [30] Hence, as its analog, tin telluride (SnTe) [21,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] with the rock-salt crystal structure has been inspired with great interests. [32] Especially, SnTe is nontoxic, earth-abundant, and environment friendly, [45] which makes it

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“…They reduce the Seebeck coefficient as the minority charge carriers contribute significantly. This is generally observed for very narrow bandgap semiconductors (E g < 0.5 eV) [13,14]. What is commonly observed is for an ideal metal, they possess high electrical conductivity and low thermal conductivity.…”

Section: Introductionmentioning

confidence: 78%

Review on texturization effects in thermoelectric oxides

Prasad

Bhame

2020

Mater Renew Sustain Energy

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Sustainable energy sources and energy-harvesting technologies have been researched for decades. Thermoelectric conversion is currently one of the primary foci in this area. Thermoelectric research has been concentrated into two parts-(i) strategies to enhance the efficiency of existing thermoelectric materials and (ii) development of new materials with promising thermoelectric parameters. Although such strategies have led to the improvement of thermoelectric non-oxide-based materials, the limitations possessed by them does not allow to be used at high temperatures. Due to the same reason, oxide-based materials have gained much attention. Here, we discuss about the oxide thermoelectric materials in detail and the effect of texturization on their morphology and transport properties. There is a lot of scope available for such class of materials for high-temperature applications.

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Investigation of the bipolar effect in the thermoelectric material CaMg₂Bi₂ using a first-principles study

Cited by 104 publications

References 47 publications

Solution-based synthesis and processing of Sn- and Bi-doped Cu₃SbSe₄nanocrystals, nanomaterials and ring-shaped thermoelectric generators

Solution-based synthesis and processing of Sn- and Bi-doped Cu₃SbSe₄nanocrystals, nanomaterials and ring-shaped thermoelectric generators

Eco‐Friendly SnTe Thermoelectric Materials: Progress and Future Challenges

Review on texturization effects in thermoelectric oxides

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Investigation of the bipolar effect in the thermoelectric material CaMg2Bi2 using a first-principles study

Cited by 104 publications

References 47 publications

Solution-based synthesis and processing of Sn- and Bi-doped Cu3SbSe4nanocrystals, nanomaterials and ring-shaped thermoelectric generators

Solution-based synthesis and processing of Sn- and Bi-doped Cu3SbSe4nanocrystals, nanomaterials and ring-shaped thermoelectric generators

Eco‐Friendly SnTe Thermoelectric Materials: Progress and Future Challenges

Review on texturization effects in thermoelectric oxides

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Investigation of the bipolar effect in the thermoelectric material CaMg₂Bi₂ using a first-principles study

Solution-based synthesis and processing of Sn- and Bi-doped Cu₃SbSe₄nanocrystals, nanomaterials and ring-shaped thermoelectric generators

Solution-based synthesis and processing of Sn- and Bi-doped Cu₃SbSe₄nanocrystals, nanomaterials and ring-shaped thermoelectric generators